Lamacz, AgnesSchweizer, Ben2016-05-092016-05-092016-03-16http://hdl.handle.net/2003/3495810.17877/DE290R-17006We investigate the acoustic properties of meta-materials that are inspired by sound-absorbing structures. We show that it is possible to construct meta-materials with frequency-dependent effective properties, with large and/or negative permittivities. Mathematically, we investigate solutions υ^ε:Ω^ε→ℝ to a Helmholtz equation in the limit ε→0 with the help of two-scale convergence. The domain Ωε is obtained by removing from an open set Ω⊂ℝⁿ in a periodic fashion a large number (order ε⁻ⁿ) of small resonators (order ε). The special properties of the meta-material are obtained through sub-scale structures in the perforations.enHelmholtz equationhomogenizationresonanceperforated domainfrequency dependent effective properties610preprint